Jesus uses this question to tell the scribes that what they are thinking is wrong. Alternate translation: "What you are thinking is wrong." or "Do not think that I am blaspheming." (See: [[rc://en/ta/man/translate/figs-rquestion]])
The word "hearts" is a metonym for their inner thoughts and desires. Alternate translation: "this inside yourselves" or "these things" (See: [[rc://en/ta/man/translate/figs-metonymy]])